Method of making trivinylaluminum



United States Patent Oflice METHOD OF MAKING TRIVINYLALUMINUM Donald J.Foster, South Charleston, and Erich Tobler,

Charleston, W. Va., assignors to Union Carbide Corporation, acorporation of New York No Drawing. Filed Aug. 10, 1959, Ser. No.832,450 6 Claims. (Cl. 260-448) This invention relates to a newcomposition of matter, trivinylaluminum and to a method of making it. Italso relates to trivinylboron, trivinylgallium, trivinylindium andtrivinylthallium.

Our new compound, trivinylaluminum is represented by the formula (CH CH)Al. It is a viscous oil at C. but cannot be kept unsolvated at roomtemperature. In the pure state it is unstable above a temperature ofabout 0 to C. It is soluble in aliphatic and aromatic hydrocarbons andforms stable etherates.

In our process trivinylaluminum is made by reacting metallic aluminumwith the vinyl derivative of an element more electronegative thanaluminum, as represented by the equation:

3 (CH CH),.M+xAl x(CH =CH) Al+3M wherein M is a metal moreelectronegative than aluminum and x is the valence of the metal. The newcompositions of matter trivinylgallium, trivinylindium andtrivinylthallium can be made by the process of our invention as can alsotrivinylboron. Depending on the compound desired, boron, gallium, indiumor thallium is reacted with a more electronegative metal such asdivinylmercury to yield the divinyl compound of the particular GroupIIIA element.

In a preferred embodiment of our process divinylmercury is reacted withmetallic aluminum foil. The divinylmercury is dissolved in an aliphatichydrocarbon such as pentane under an inert atmosphere such as nitrogenand the aluminum foil is added to the solution at any temperature frombelow 0 C. to as high as the boiling point of the aliphatic solvent. Thealuminum begins to dissolve almost immediately and soon disappears whilea pool of molten mercury forms. The supernatant liquid containing thealiphatic hydrocarbon solvent and trivinylaluminum is separated from themercury and the solvent is then removed under reduced pressure to yieldthe desired trivinylaluminum product.

Divinylmercury is a preferred reagent. Also useful, however, are vinylcompounds of metals more electronegative than aluminum. Divinylmercurymay be made by adding mercuric chloride to vinylsodium in a solvent suchas butyl ether.

While the use of a solvent is not essential to the process, it ispreferred to employ an aliphatic hydrocarbon solvent in which thetrivinylaluminum is soluble and stable for some time at room temperatureor above. Any solvent may be employed which is substantially inert tothe reactants and the products and in which they are both soluble, forexample aromatic hydrocarbons. We have found, however, that in generalamines, alcohols, ethers and carbonyl-containing compounds tend toeither react with the product or form such strongly bonded complexeswith it that isolation of the pure product is impaired. Suitablesolvents include pentane, hexane, heptane, benzene, toluene, xylene andthe like.

If no solvent is employed the reaction temperature must be kept belowabout 0 C. to 10 C. because of the instability of unsolvatedtrivinylaluminum above these temperatures. While the use of an aliphatichydrocarbon solvent permits reaction temperatures of 100 C. or above, itis preferred to maintain the reaction temperature at 25 C. or below dueto the tendency of trivinylaluminum to decompose with time at elevatedtemperatures. Temperatures below about 30 C. are avoided because of are- 3,258,476 Patented June 28, 1966 duction in the reaction rate with adecrease in temperature. An inert atmosphere such as dry nitrogen isemployed to minimize decomposition of the product. The rare gases andhydrocarbon gases may also be used as they do not react withtrivinylalumium.

In the process of the invention the stoichiometric quan tities ofreagents are preferred, but the ratios of reactants are not narrowlycritical and can be widely varied without affecting the outcome of thereaction. While aluminum foil is a preferred form of aluminum for thereaction it can be any form small enough for reaction, as in a powder,slivers, granules, turnings, etc.

We obtained proof of the composition as trivinylaluminum in severalways. Elemental analysis agreed with the calculated value fortrivinylaluminum. The product was reacted with acetone and subsequentlyhydrolyzed to give dimethylvinylcarbinol, a known compound. In thisreaction the mercury was removed prior to the addition of acetone and,in addition, under similar conditions, divinylmercury does not reactwith acetone. As a final test trivinylaluminum was reacted with water togive ethylene and aluminum hydroxide.

Trivinylaluminum is useful as an intermediate for organic synthesis asare trivinylgallium, trivinylindium and trivinylthallium.Trivinylaluminum is highly pyrophoric and hence is useful for thisproperty. For example it can be added in small quantities to fuels forjet engines to prevent so-called flame-outs. Also it can be mixed withhydrocarbon rocket fuels in concentrations up to 30 percent in order toimprove burning and reduce screech.

Example I To 15.3 grams (0.06 mol) of divinylmercury dissolved in 200milliliters of dry pentane was added 1.1 grams (0.04 gram atom) ofaluminum foil. The entire reaction was conducted in an atmosphere ofhigh purity nitrogen. The reaction temperature was maintained at about20 C. and almost immediately there was evidence for solution of thealuminum and deposition of mercury. Within minutes all of the aluminumhad disappeared and a pool of liquid mercury could be removed from thereaction flask. A total of 83 percent by weight of the theoreticalamount of mercury was recovered. The temperature of the product solutionwas then lowered to 20 C. while the pentane was removed by reducing thepressure. The product was a viscous oil with a faint yellow colorationand consisted of trivinylaluminum. An elemental analysis of the compoundwas made with the following result:

Calculated for C H Al: C, 66.6; H, 8.39; Al, 24.95. Found: C, 65.8; H,8.4; Al 25.7.

Upon warming to a temperature of 0 C. to 10 C. the trivinylaluminumdecomposed to a yellow-brown solid with a sponge-like consistency.

Example II To 15.3 grams (0.06 mol) of divinylmercury dissolved in 200milliliters of dry pentane was added 1.1 grams (0.04 gram atom) ofaluminum foil. The reaction was conducted in an atmosphere of highpurity nitrogen at a temperature of about 20 C. After about 75 minutesthe reaction was complete and to the product mixture there was added asolution of 7.0 grams (0.12 mol) of acetone in 10 milliliters ofpentane. The ensuing reaction was exothermic and after it had subsidedwater was added to hydrolyze the product. The organic layer was thenseparated and dried over anhydrous sodium sulfate, after which it wasdistilled. A material boiling at a temperature of 98-9 C. was isolatedand proved to be identical, both chemically and spectrographically, witha sample of dimethylvinylcarbinol prepared by the reaction ofvinylmagnesium bromide with acetone.

3 Example III Trivinylaluminum was prepared in the manner of Example Iand the product was hydrolyzed with water. The evolved gas was collectedand analyzed by means of a mass spectrometer. The gaseous material wasalmost exclusively ethylene with only trace amounts of hydrogen andconcentrates. The yield of trivinylaluminum calculated from the evolvedethylene was over 80 percent of the theoretical.

Example IV A butyl ether slurry containing 135 grams (0.5 mol) ofmercuric chloride was added portion-wise to a butyl ether suspensioncontaining 50 grams (1.0 mol) of vinylsodium maintained at a temperatureof about minus C. After the addition was complete, the reaction mixturewas stirred for an additional thirty minutes before it was allowed tocome to room temperature. Water was added to hydrolyze unreactedstarting material and dissolved the inorganic salts. The organic layerwas dried over magnesium sulfate and distilled at a reduced pressure ofmillimeters of mercury. After removal of the solvent, the product boiledat a temperature of 59 C. to 61 C. at 20 millimeters. This product wasdivinylmercury.

What is claimed is:

1. Process for making trivinylaluminum which comprises reacting aluminumwith (CHFCH) M wherein M is a metal more electronegative than aluminumand x is the valence number of the metal, said process being conductedat a temperature of from 30 C. to 10 C.

2. Process as claimed in claim 1 wherein M is mercury and x is 2.

3. Process for making trivinylaluminum which comprises reacting aluminumwith (CH =CH) M wherein M is a metal more electronegative than aluminumand x is the valence number of the metal, said process being conductedat a temperature of from 30 C. to C. in an aliphatic hydrocarbonsolvent.

4. Process as claimed in claim 3 wherein M is mercury and x is 2.

5. The process for preparing trivinylaluminum which comprises reactingmetallic aluminum with divinylmercury at about 20 C. until the reactionis substantially complete.

6. The process for preparing trivinylaluminum which comprises reactingmetallic aluminum with divinyl mercury under conditions conducive to theformation of trivinylaluminum, and recovering trivinylaluminum from theproduct of said reaction.

References Cited by the Examiner UNITED STATES PATENTS 2,921,954 1/1960Ramsden 260429.7 3,010,985 11/1961 Ramsden 260448 OTHER REFERENCESBeilsteins Handbuch der Organischen Chemie, 4th Edition, 2nd Addition tovol. IV (1942), page 1024.

European Scientific Notesvol. 6, No. 13 (July 1, 1952), page 178 (pub.by Office of Naval Research, London).

Grosse et al., Die Chemie der metall-organischen Verbindung (1937), page12.

TOBIAS E. LEVOW, Primary Examiner.

ABRAHAM H. WINKELSTEIN, Examiner.

6. THE PROCESS FOR PREPARING TRIVINYLALUMINUM WHICH COMPRISES REACTINGMETALLIC ALUMINUM WITH DIVINYL MERCURY UNDER CONDITIONS CONDUCTIVE TOTHE FORMATION OF TRIVINYLALUMINUM, AND RECOVERING TRIVINYLALUMINUM FROMTHE PRODUCT OF SAID REACTION.